Composites of a matrix reinforced with wood fiber and other short cellulose fiber are described by Boustany and Coran U.S. Pat. No. 3,697,364, Oct. 10, 1972, the disclosure of which is incorporated herein by reference. The pretreatment of the fiber with organic polymer to effect predispersion and minimize fiber damage upon subsequent mixing into the matrix is described as an essential part of a process for preparing high performance composites. Improvements in the pretreatment of wood fiber with organic polymers are described by Hamed U.S. Pat. No. 3,943,079, Mar. 9, 1976. The conjoint use of a lubricant such as process oil enhances receptiveness of the fiber to the polymer. The present invention provides a process of preparing composites of wood pulp and elastomers without such pretreatment.